The correct answer is option 1.

Leaves of lotus and water lily are not easily wet because they have a surface that is uneven on a micro-scale. This uneven surface prevents water from coming into contact with the depressed areas of the leaf, due to the high surface tension of water. Surface tension is a property of water that causes it to form droplets and not spread out over a surface.

The micro-scale unevenness of the leaf surface creates multiple tiny bumps and ridges that trap air pockets, which further prevents water from spreading and wetting the leaf. As a result, water beads up and rolls off the surface of the leaf, giving the impression that the leaf is not getting wet.

Options 2 and 3 suggest that the leaves contain oily or greasy substances, but this is not the primary reason why the leaves are not easily wet. While it is true that the presence of these substances can contribute to water repellency, the main factor is the surface structure of the leaves.

Option 4 is incorrect because the smoothness or roughness of a surface does not determine its ability to repel water. In the case of lotus and water lily leaves, it is the micro-scale unevenness that plays the crucial role in